I have been victim of a seller on eBay and bought what I thought was a working 9900. However although it "works" in strict sense, all caps are swollen and output transistors are all different and Wire from pin 6 of protection circuit is also missing. Essentially it looks like dogs dinner and I cannot contact the seller , reported to eBay. Original output transistors should have been 2SA679/2sc1079 , what are the modern day replacements for them? I will upload pictures shortly.